Malate root metabolism in processes associated with the maintaining of cellular water status

ARIAS, C. L.; BADIA, M. B.; ANDREO, C. S.; DRINCOVICH, M. F.; GERRARD WHEELER, M. C.; SAIGO, M.

Mar del Plata

Congreso; LI Reunión Anual SAIB; 2015

SAIB

Water scarcity is a major cause of crop lossesworldwide and great efforts are being made to achieve drought tolerant crops,especially in countries like Argentina, whose economy is based on the agriculturalproduction. In Arabidopsis cells, the malic enzyme (ME) family is representedby four enzymes which catalyze the malate oxidative decarboxylation in thepresence of NADP. NADP-ME1 is a cytosolic isoform which stands out due to its evolutionarilyconservation, delimited expression to roots and kinetic characteristics. Here,a more detailed analysis using reporter gene fusions showed the presence ofNADP-ME1 in the region of maturation. The treatment with absicic acid (ABA), adrought response mediator, specifically induced the expression of NADP-ME1 inthe meristematic cells. Inline with this, Arabidopsis mutantplants lacking NADP-ME1 presented an increased resistance to drought and lowerresponse of root growth to ABA. These results suggest that NADP-ME1 plays avery specialized role in roots possiblyregulating the concentration of the substrates and/or reaction products to feedmetabolic pathways and regulatory functions triggered by the water stress signal.